# Relative Filters 1.0

## Candidate Recommendation 28 March 2008

Copyright ©2008 XBRL International Inc., All Rights Reserved.

This version:
  <http://www.xbrl.org/Specification/relativeFilters/CR-2008-03-28/relativeFilters-CR-2008-03-28.html>
Editors:
  Phillip Engel, Morgan Stanley <phillip.engel@morganstanley.com>
  Herm Fischer, UBMatrix / Mark V Systems <fischer@markv.com>
  Victor Morilla, Banco de España <victor.morilla@bde.es>
  Jim Richards, JDR & Associates <jdrassoc@iinet.net.au>
  Geoff Shuetrim, Galexy <geoff@galexy.net>
  David vun Kannon, PricewaterhouseCoopers LLP <david.k.vunkannon@us.pwc.com>
  Hugh Wallis, XBRL International <hughwallis@xbrl.org>
Contributors:
  Cliff Binstock, Coyote Reporting <cliff.binstock@coyotereporting.com>
  Paul Bull, Morgan Stanley <paul.bull@morganstanley.com>
  Mark Goodhand, Decisionsoft <mrg@decisionsoft.com>
  Masatomo Goto, Fujitsu <mg@jp.fujitsu.com>
  Walter Hamscher, Standard Advantage / Consultant to PricewaterhouseCoopers LLP <walter@hamscher.com>
  Ignacio Hernández-Ros, Reporting Estandar S.L. <ignacio@hernandez-ros.com>
  Roland Hommes, Rhocon / Consultant to Netherlands Tax and Customs Administration <roland@rhocon.nl>
  Andy Harris, UBMatrix <andy.harris@ubmatrix.com>
  Pablo Navarro Salvador, Atos Origin sae <pablo.navarro@atosorigin.com>
  Michele Romanelli, Banca d'Italia <michele.romanelli@bancaditalia.it>
  Chris Simmons, DecisionSoft <cps@decisionsoft.com>
  Masaru Uchida, Fujitsu <m-uchida@jp.fujitsu.com>
  Hitoshi Okumura, Fujitsu <okmr@jp.fujitsu.com>
  Takahide Muramoto, Fujitsu <taka.muramoto@jp.fujitsu.com>

## Status

Circulation of this Candidate Recommendation is unrestricted. This document is normative. Other documents may supersede this document. Recipients are invited to submit comments to formula-feedback@xbrl.org, and to submit notification of any relevant patent rights of which they are aware and to provide supporting documentation.

## Abstract

This specification defines syntax for a filter that supports conditioning upon matching the value of all uncovered aspects of a fact to the corresponding aspects of other facts.

# 1 Introduction

This specification is an extension to the XBRL Variables Specification [VARIABLES]. It defines XML syntax [XML] for a filter that supports conditioning upon matching the value of all uncovered aspects of a fact to the corresponding aspects of other facts.

The relative filter identifies a fact variable that aspects are to be matched against. The uncovered aspect values for a fact variable with a relative filter are determined in relation to the uncovered aspect values of the facts matched by the variable identified by the relative filter.

For some variable-sets, relative filtering can provide a finer level of matching control than that available with implicit filtering, as defined in the Implicit filtering specification [IMPLICIT FILTERS].

## 1.1 Background

This specification is a member of a suite of similar specifications that define specific types of criteria that can be used to select facts from XBRL instances. It enhances the fact selection capabilities of the XBRL Variables Specification [VARIABLES].

## 1.2 Relationship to other work

This specification depends upon the XBRL Specification [XBRL 2.1], the XBRL Variables Specification [VARIABLES]. In the event of any conflicts between this specification and the specifications upon which it depends, this specification does not prevail.

## 1.3 Language independence

The official language of XBRL International's own work products is English and the preferred spelling convention is UK English.

## 1.4 Terminology

This specification is consistent with the definitions of any of the terms defined in specifications that it depends on.

## 1.5 Document conventions (non-normative)

Documentation conventions follow those set out in the XBRL Variables Specification [VARIABLES].

## 1.6 Namespaces and namespace prefixes

Namespace prefixes [XML NAMES] will be used for elements and attributes in the form `ns:name` where `ns` is the namespace prefix and `name` is the local name. Throughout this specification, the mappings from namespace prefixes to actual namespaces is consistent with Table 1.

The prefix column in Table 1 is non normative. The namespace URI column is normative.

Table 1: Namespaces and namespace prefixes

Prefix | Namespace URI
--- | ---
`rf` | `http://xbrl.org/2008/filter/relative`
`xbrlrfe` | `http://xbrl.org/2008/filter/relative/error`
`eg` | `http://example.com/`
`fn` | `http://www.w3.org/2005/xpath-functions`
`link` | `http://www.xbrl.org/2003/linkbase`
`xbrli` | `http://www.xbrl.org/2003/instance`
`xfi` | `http://www.xbrl.org/2005/function/instance`
`xbrldi` | `http://xbrl.org/2006/xbrldi`
`xbrldt` | `http://xbrl.org/2005/xbrldt`
`xl` | `http://www.xbrl.org/2003/XLink`
`xlink` | `http://www.w3.org/1999/xlink`
`xs` | `http://www.w3.org/2001/XMLSchema`
`xsi` | `http://www.w3.org/2001/XMLSchema-instance`
`gen` | `http://xbrl.org/2008/generic`
`variable` | `http://xbrl.org/2008/variable`
`iso4217` | `http://www.xbrl.org/2003/iso4217`

## 1.7 XPath usage

XPath usage is identical to that in the XBRL Variables Specification [VARIABLES].

# 2 Syntax

This specification only provides a textual declaration of syntax constraints when those constraints are not expressed by the normative schema supplied with this specification.

Explanations of elements and attributes are only supplied when explanations are not already provided in other specifications.

Unless explicitly stated otherwise, a reference to a specific element MUST be read as a reference to that element or to any element in its substitution group.

## 2.1 Relative filters

A relative filter is declared by an `<rf:relativeFilter>` element.

The syntax for the `<rf:relativeFilter>` element is defined by the normative schema supplied with this specification.

A relative filter covers all or none of the aspects that are not covered by other filters. If a relative filter does cover aspects then the fact variables that it is associated with have no uncovered aspects.

The relative filter can be used to select facts for which the aspects that are covered by the relative filter, have values that match the corresponding aspects of another fact.

The fact that is being matched to by the relative filter MUST be the evaluation result of another fact variable in the variable set being evaluated.

The aspects that are matched by a relative filter are determined by the aspect model of the variable set.

The XPath expression implied by a relative filter is constructed as an and-expression from the implied XPath expressions of the matching filters [MATCH FILTERS] that match each of the aspects in the variable set's aspect model that can be covered by the relative filter.

The implied value of the `@variable` attribute for each of the matching filters is equal to the value of the `@variable` attribute on the relative filter.

For aspect models that include segment dimension aspects or scenario dimension aspects the implied value of the `@dimension` attribute for each of the segment or scenario dimension matching filters is equal to the QName of the dimension that is being matched.

Example 1 shows the small number of filters required to define variables that would support stock flow computations. All of the aspects except for the concept, the period and the restatement date typed dimension are matched for the two variables by the relative filter. The relative filter provides an alternative to implicit filtering, as defined in the Implicit filter specification [IMPLICIT FILTERS], for matching the values of many aspects.

Example 1: Variables that could support calculation of end-of-period stocks.

Variables in the variable set
Variable | Filters
--- | ---
`eg:flow` | covering concept-name filter requiring matching facts to report values for the `eg:flow` concept.
`eg:startingStock` | covering concept-name filter requiring matching facts to report values for the `eg:stock` concept. covering instant-duration filter requiring matching facts to report values with an instant equal to the start of the duration of the fact matched by the `eg:flow` variable. covering typed dimension filter requiring matching facts to report values with a restatement date that is equal to the end date of the fact matched by the `eg:flow` variable. covering relative filter matching otherwise uncovered aspects to the fact that variable `eg:flow` has evaluated to. 1

1. The use of a non-dimensional aspect model would not be possible for this variable set given the need to filter based on the `eg:restatementDate` typed dimension.

Example 2 shows the small number of filters required to define variables that would support computation of equity from total assets and total liabilities. All of the aspects except for the concept, are matched for the two variables by the relative filter. Again the relative filter provides an alternative to implicit filtering, as defined in the Implicit filter specification [IMPLICIT FILTERS], for matching the values of many aspects.

Example 2: Variables that could support equity calculation formulae.

Variables in the variable set
Variable | Filters
--- | ---
`eg:assets` | covering concept-name filter requiring matching facts to report values for the `eg:assets` concept.
`eg:liabilities` | covering concept-name filter requiring matching facts to report values for the `eg:liabilities` concept. covering relative filter matching otherwise uncovered aspects to the fact that variable `eg:assets` has evaluated to. 1

1. The use of a non-dimensional aspect model would make this variable set innappropriate for use with XBRL instances that make use of XBRL Dimensions [DIMENSIONS] because matching of segments and scenarios would not take subtleties relating to comparison of XBRL Dimension values into account.

# Appendix A Normative schema

The following is the XML schema provided as part of this specification. This is normative. Non-normative versions (which should be identical to these except for appropriate comments indicating their non-normative status) are also provided as separate files for convenience of users of the specification.

NOTE: (non-normative) Following the schema maintenance policy of XBRL International, it is the intent (but is not guaranteed) that the location of non-normative versions of these schemas on the web will be as follows:

1. While any schema is the most current RECOMMENDED version and until it is superseded by any additional errata corrections a non-normative version will reside on the web in the directory `http://www.xbrl.org/2008/` - during the drafting process for this specification this directory should contain a copy of the most recent published version of the schema at http://www.xbrl.org/2008/relative-filter.xsd.
2. A non-normative version of each schema as corrected by any update to the RECOMMENDATION will be archived in perpetuity on the web in a directory that will contain a unique identification indicating the date of the update.

<schema xmlns:rf="http://xbrl.org/2008/filter/relative" xmlns:variable="http://xbrl.org/2008/variable" xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://xbrl.org/2008/filter/relative" elementFormDefault="qualified">
<import namespace="http://www.xbrl.org/2003/XLink" schemaLocation="http://www.xbrl.org/2003/xl-2003-12-31.xsd"/>
<import namespace="http://xbrl.org/2008/variable" schemaLocation="variable.xsd"/>
<element id="xml-relative-filter" name="relativeFilter" substitutionGroup="variable:filter">
<complexType mixed="true">
<complexContent mixed="true">
<extension base="variable:resource.type">
<attribute name="variable" type="QName" use="required"/>
</extension>
</complexContent>
</complexType>
</element>
</schema>

# Appendix B References

CONCEPT FILTERS
  XBRL International Inc.. "XBRL Concept Filters 1.0, Public Working Draft"
  Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See ../../conceptFilters/CR-2008-03-28/conceptFilters-CR-2008-03-28.html)
DIMENSION FILTERS
  XBRL International Inc.. "XBRL Dimension Filters 1.0, Public Working Draft"
  Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See ../../dimensionFilters/CR-2008-03-28/dimensionFilters-CR-2008-03-28.html)
DIMENSIONS
  XBRL International Inc.. "XBRL Dimensions 1.0"
  Ignacio Hernández-Ros, and Hugh Wallis.
  (See http://www.xbrl.org/Specification/XDT-REC-2006-09-18.htm)
IMPLICIT FILTERS
  XBRL International Inc.. "XBRL Implicit Filters 1.0, Public Working Draft"
  Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See ../../implicitFilters/CR-2008-03-28/implicitFilters-CR-2008-03-28.html)
MATCH FILTERS
  XBRL International Inc.. "XBRL Match Filters 1.0, Public Working Draft"
  Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See ../../matchFilters/CR-2008-03-28/matchFilters-CR-2008-03-28.html)
PERIOD FILTERS
  XBRL International Inc.. "XBRL Period Filters 1.0, Public Working Draft"
  Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See ../../periodFilters/CR-2008-03-28/periodFilters-CR-2008-03-28.html)
VARIABLES
  XBRL International Inc.. "XBRL Variables 1.0, Public Working Draft"
  Phillip Engel, Herm Fischer, Victor Morilla, Jim Richards, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See ../../variables/CR-2008-03-28/variables-CR-2008-03-28.html)
XBRL 2.1
  XBRL International Inc.. "Extensible Business Reporting Language (XBRL) 2.1"
  Phillip Engel, Walter Hamscher, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
  (See http://www.xbrl.org/Specification/XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2006-12-18.htm)
XML
  W3C (World Wide Web Consortium). "Extensible Markup Language (XML) 1.0 (Fourth Edition)"
  Tim Bray, Jean Paoli, C. M. Sperberg-McQueen, Eve Maler, and François Yergeau.
  (See http://www.w3.org/TR/REC-xml/)
XML NAMES
  W3C (World Wide Web Consortium). "Namespaces in XML 1.0 (Second Edition)"
  Tim Bray, Dave Hollander, Andrew Layman, and Richard Tobin.
  (See http://www.w3.org/TR/REC-xml-names/)
XML SCHEMA STRUCTURES
  W3C (World Wide Web Consortium). "XML Schema Part 1: Structures Second Edition"
  Henry S. Thompson, David Beech, Murray Maloney, and Noah Mendelsohn.
  (See http://www.w3.org/TR/xmlschema-1/)
XPATH 2.0
  W3C (World Wide Web Consortium). "XML Path Language (XPath) 2.0"
  Anders Berglund, Scott Boag, Don Chamberlin, Mary F. Fernández, Michael Kay, Jonathan Robie, and Jérôme Siméon.
  (See http://www.w3.org/TR/xpath20/)

# Appendix C Intellectual property status (non-normative)

This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to XBRL International or XBRL organizations, except as required to translate it into languages other than English. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).

This document and the information contained herein is provided on an "AS IS" basis and XBRL INTERNATIONAL DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

The attention of users of this document is directed to the possibility that compliance with or adoption of XBRL International specifications may require use of an invention covered by patent rights. XBRL International shall not be responsible for identifying patents for which a license may be required by any XBRL International specification, or for conducting legal inquiries into the legal validity or scope of those patents that are brought to its attention. XBRL International specifications are prospective and advisory only. Prospective users are responsible for protecting themselves against liability for infringement of patents. XBRL International takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).

# Appendix D Acknowledgements (non-normative)

This document could not have been written without the contributions of many people including the participants in the Formula Working Group.

# Appendix E Document history (non-normative)

Date | Author | Details
--- | --- | ---
18 December 2006 | Geoff Shuetrim | First internal working draft created, drawing extensively on the previous formula specification drafts
25 April 2007 | Geoff Shuetrim | Changed the target namespace for the normative schema.
29 May 2007 | Geoff Shuetrim | Changed the target namespace of the normative schema again. Changed the implied XPath expressions to be consistent with the structures used for the period filters. Changed XPath expression references to $x to #x to be consistent with other filter specifications. Changed the value attribute data types to allow XPath 2.0 expressions rather than constants.
25 June 2007 | Geoff Shuetrim | Added material to the introduction on the implications of entity filters for implicit filtering.
24 July 2007 | Hugh Wallis | Edited for public working draft publication.
05 November 2007 | Geoff Shuetrim | Converted the specification to XML format. Added in the definitions and the hyperlinks to the relevant sections of the normative schema. Added comments about simplifications that should be made.
05 November 2007 | Geoff Shuetrim | Completed the first draft of the relative filtering specification, reflecting a simplified version of the implicit filtering approach that featured in the second public working draft released in July 2007. Added a dimensional/non-dimensional relative filter distinction to enable relative filtering in a way that is or is not aware of the XBRL Dimensions Specification [DIMENSIONS].
01 December 2007 | Geoff Shuetrim | Added examples. Simplified relative filters by ensuring that their aspect models are determined by the aspect model of the variable set that they are being used with. This eliminates the potential for conflicts between the aspect models implied by the relative filter and the aspect model of the variable set. It also ensures that a given variable can be better re-used in two different variable sets that use different aspect models, without distorting the operation of the relative filtering mechanism.
24 January 2008 | Geoff Shuetrim | Made the `@variable` attribute on the relative filter required in the normative schema.
31 January 2008 | Geoff Shuetrim | Standardised the format of the hyperlinks to the normative schema.
13 March 2008 | Geoff Shuetrim | Explained the examples better and provided more detail on the relationship to implicit filtering, as suggested by CompSci Resources.

# Appendix F Errata corrections in this document

This appendix contains a list of the errata that have been incorporated into this document. This represents all those errata corrections that have been approved by the XBRL International Formula Working Group up to and including 28 March 2008. Hyperlinks to relevant e-mail threads may only be followed by those who have access to the relevant mailing lists. Access to internal XBRL mailing lists is restricted to members of XBRL International Inc.

No errata have been incorporated into this document.